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Publication numberUS3692106 A
Publication typeGrant
Publication dateSep 19, 1972
Filing dateApr 12, 1971
Priority dateApr 12, 1971
Also published asCA968929A, CA968929A1
Publication numberUS 3692106 A, US 3692106A, US-A-3692106, US3692106 A, US3692106A
InventorsBasham Edward R, Smith William D
Original AssigneeBasham Edward R, Smith William D
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for ejecting fluid in a borehole
US 3692106 A
Abstract
An improvement in apparatus for ejecting a fluid in a borehole penetrating subterranean formations characterized by; in addition to the conventional surface equipment, wireline, and downhole tool; a motor driving an accurate dispensing cylinder and piston, and a measuring and stopping means connected with the motor for measuring when a predetermined quantity of fluid has been ejected and for stopping the motor. Also disclosed are other aspects of a complete apparatus assembly including:
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wuuv uuo 135-1 1 1 unlteu mates talent us] 3,692,106 Basham et al. [451 Sept. 19, 1972 [54] APPARATUS FOR EJECTING FLUID IN A BOREHOLE Primary Examiner-James A. Leppink 72 Inventors: Edward R. Basham, 4125 Driskell, Mamekwdfmdjelsma Fans Forth Worth, Tex, 76107; William D. Smith, 4217 Sarita, Forth Worth, [57] ABSTRACT Tex. 76109 An improvement in apparatus for ejecting a fluid in a borehole penetrating subterranean formations charac- [22] Filed 1971 terized by; in addition to the conventional surface [21] Appl. No.: 133,155 equipment, wireline, and downhole tool; a motor driving an accurate dispensing cylinder and piston, and a [52] Us Cl 166,53 l66/64' l66/66 measuring and stopping means connected with the {66/104 '166/l69 motor for measuring when a predetermined quantity Int Cl Ezlb 43/00 of fluid has been ejected and for stopping the motor.

[58] Field of Search ..166/53, 65,66, 72, 104, 162, dimmed are aspects a complee paratus assembly including: 1. a sensor means in the downhole tool;'

' 7 I 2. a timed relay and switch for supplying a timed [56] 1 References Cited power pulse to the motor and thereafter monitor- UNITED STATES PATENTS mg the sensor means; and

3. specific structure and electrical schematic dia- Hassler grams for improving the accuracy of the ejection 2,631,673 3/1953 Halderson et al ..l66/l69 f the q y of fluid, and for f n g the 2,928,471 3/1960 Jones 166/ 162 downhole tool at the surface 3,273,647 9/1966 Briggs, Jr. et a1. ..l66/l69 3,433,302 3/1969 Shore ..166/ 162 21 Claims, 5 Drawing Figures COUNTER 11% FILTER 27 4 59 D.c. POWER D.C. POWER PULSE RATE SUPPLY "A" SUPPLY "B" COUNTER TIMED RELAY RECORDER PAIENTED EP 1 I9 3. 6 92.106

sum 1 or 2 COUNTER 45 v FILTER 0.0. PowER D.C. POWER PULSE RATE SUPPLY "A" SUPPLY "B" COUNTER T M E D RELAY RECORDER L9 L 37) l r 2 CAM ACTUATOR '5 w o 7 i I l 49 i 1 7 59 4/ 7 E 75 i 47 IQ? 65 6/ 2-; E I 2 In HE /6 7 i 7/ I?" ,I A;

M3 w 23 By 0 /65 i lNVENTORS, i J fly/zmyflfififlshflm/ WzZ/Mmflfimfi H -J. M 422a):

// ATTORNEYS PATENTEBSEP 1 9 1912 SHEU 2 [1F 2 ATTOHNE Y5 APPARATUS FOR EJECTING FLUID IN A BOREIIOLE BACKGROUND OF THE INVENTION lates to improvements in apparatus for releasing a 1 quantity of a fluid in a borehole penetrating subterranean formations and monitoring a parameter that is responsive to the release 'of the fluid.

2. Description of the Prior Art Fluids have been released from a downhole tool in a borehole penetrating subterranean formations for a wide variety of purposes in the prior art. It is known in the prior art, for example, to release a quantity of a fluid containing radioactive material from a downhole tool stationed at a particular depth in the borehole. The downhole tool also contains a sensor means that is capable of deriving meaningful information by monitoring a parameter; such as, a product of radioactivity of the radioactive material for a quantitative measurement of the flow of the radioactive material in a fluid flowing past the sensor means. The product of radioactivity may comprise gamma rays emitted directly or back scattered. The product of the radioactivity is used for obtaining a quantitative indication of any one of a variety of parameters; such as, quantity of flow, as for a flow profile, either in an injection well or a production well in which a fluid is flowing into or from strata of the subterranean formation. The-product of the radioactivity is monitored by a conventional appropriate sensor means such as a Geiger counter. As is known, the sensors like the Geiger counter convert the product of the radioactivity into pulses. The pulses of electrical energy are sent to the surface to be monitored, as will become apparent from the description of FIG. l hereinafter. If random quantities, or volumes, of liquid; including the similar random quantities of radioactive material are released; unreliable and inaccurate measurements result. The prior art has suffered from such a defect. It is believed readily apparent that quantitative measurements are possible only if a predetermined, or metered, quantity of the fluid is released, or ejected, each ejection cycle.

In the closest prior art apparatus, an operator at the surface depressed a manual switch to effect operation of a downhole motor and eject a quantity of fluid. The quantity of fluid was only as accurate as the period of time the operator depressed the button. Even with a skilled operator, the variations in thelengths of cable through which the electrical connection was made caused variations in the quantity of fluid that was released. The results of the prior art apparatus can at best be described as erratic. Specifically, the prior art did not provide the following desirable features:

1. accurate control of the quantity of fluid that was ejected during each ejection cycle as effected by accurately controlling the degrees of rotation of the shaft of the motor, generally referred to as degrees of angular rotation of the motor;

2. a timed power pulse that was only slightly longer than the time required to eject the fluid and, thereafter, effect accurate monitoring over economical single conductor grounded cable;

3. structure which prevented unwanted flow of the material from the tool because of pressure flow effects; such as the Bernoulli effects due to relative movement between the downhole tool and fluid in the borehole; and

4. a readily accessible reversing bypass for refilling of the tool at the surface without requiring disassembly of the downhole tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational view of one embodiment of this invention.

FIG. 2 is an electrical schematic diagram of the circuit employed in the dynamic braking circuit of the downhole tool in the embodiment of FIG. 1.

FIG. 3 is a side cross sectional view of an upper portion of an ejector section of the downhole tool of the embodiment of FIG. 1.

FIG. 4 is a side cross sectional view of the lower portion of the ejector section of the downhole tool of the embodiment of FIG. 1.

FIG. 5 is a partial isometric view of the cam actuator and switch means of FIG. 2.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS It is a primary object of this invention to obviate the disadvantages of the prior art apparatus and to reliably eject a predetermined and known quantity of a fluid from a downhole tool into a borehole penetrating subterranean formations.

It is also an object of this invention to provide the respective desirable features delineated hereinbefore and not provided by the prior art apparatus.

These and other objects will be apparent from the following description taken in conjunction with the accompanying drawings.

Referring to FIG. 1, a downhole tool 11 is suspended in a cased borehole 13 by a cable means such as wireline 15. The downhole tool includes an ejector section 19, a casing collar locator section 21, and a sensor means such as radioactivity detector section 23.

The cable means 15 may be any one of the plurality of conventional cables. The cable means will have at least one conductor such as conductor 41 serially connected with the surface equipment and the downhole tool 11. It will also have a ground 51; such as an armored sheath as indicated by the ground symbol. On the other hand, the cable may be a coaxial cable having a plurality of conductors that are shielded to preserve fidelity of the downhole signals. As illustrated, the

wireline 15 is of conventional type known as single conductor line, although it in fact has in a protective armor that serves as a ground for effecting a complete electrical circuit.

The borehole tool 11 has an elongate body means that comprises a plurality of tubular sections for housing respective subassemblies, and is adapted for traversing along the longitudinal axis of the borehole 13. The borehole tool 11 has a cable attachment means such as cable head 17 at its upper end for physically and electrically connecting with the cable means 15. The ejector section 19 is connected to the cable head 17 as by threaded connection with appropriate electrical connector plugs and sockets. As illustrated, the

tion. These accurate injection profiles require a plurality of ejection cycles and attendant measurements responsive to the ejected fluid.

The term fluid is employed herein to mean any fluid-like materialincluding but not limited to gases, liquids, gels, and other non-Newtonian fluids like suspensions. The type of fluid ejected will depend in large part upon the type of injection fluid. Foi" example, where the injection fluid is a gas, radioactive gases such as krypton and bromine may be employed. On the other hand, where the injection fluid is a liquid, a liquid material containing radioactive material or isotopes; such as, radioactive iodine, iridium, or cobalt; may be employed. Ordinarily, the radioactive materials with short half lives are preferred. The radioactive materials may be water soluble or oil soluble depending upon whether the borehole liquid is water or oil. Such radioactive materials and their use is well understood in the art and need not be described further herein.

The surface equipment includes a current regulated, direct current (D.C.) power supply A 25, a counter 27 and a timed relay means and switch means such as timed relay 29 operatively connected with switch 31, all of which cooperate to supply power to the ejector section 19 for effecting ejection of fluid therefrom. The surface equipment further includes a direct current power supply B 33, a pulse rate counter 35, and a recorder 37, all of which cooperate for decoding or converting a signal from the radioactivity detector section 23 and displaying a representation of the parameter being monitored thereby. In addition, the surface equipment includes a filter 39 for passing the signals from the casing collar locator 21 in order to provide an indication of collar location on the strip chart output from recorder 37 for a more accurate correlation of depth on the record of the representation from pulse rate counter 35.

As indicated, the timed relay 29 controls the contacts of the single pole switch 31. The timed relay 29 is normally stable in a first condition so as to maintain switch 31 as indicated in FIG. 1, connecting the DC. power supply B with the wireline 15, such that the radioactivity detector section 23 andthe casing collar locator 21 are operatively connected with the recorder 37. The timed relay 29 is operable into a second condition, however, to connect, for a predetermined interval of time, the DC. power supply A 25 onto the cable 15. The timed relay 29 may be energized into its second condition by depression of a manually operated control means such as switch 30. Suitable timed relays are known in varying forms ranging from electronic devices such as mono stable multivibrators to combinations of biased relays and timers. The timed relay 29 includes its own power source (not shown). Specifically,

with the switch 31 in the position indicated, a first circuit may be traced via conductor 41 and switch 31 to DC power supply B 33 from the cable 15, thereby supplying power to the radioactivity detector 23. A second circuit may be traced from conductor 41 through switch 31 and coupling capacitor 43 to the input of the pulse rate counter 35, the output of which is also connected to the recorder. When the contacts of the switch 31 are in the left hand, or second, position, corresponding to the second condition of the timed relay 29, then the conductor 41 is connected through the switch 31 and in series with the counter 27 and the direct current power supply A 25; thereby supplying power of opposite polarity to the motor in the ejector section 19.

In the preferred embodiment where fluid flow measurements are being made in the borehole 13 in order to determine an injection flow profile, the radioactivity detector 23 is preferably of the dual type. As is well known, in the dual type radioactivity detectors, there are two detector devices such as the aforementioned Geiger counters that are spaced a known distance apart. This type of radioactivity detector is conventional and well known and need not be described in detail herein.

It is sufficient to note that the outputs of the radioactivity detectors are conveyed in a conventional manner by the wireline l5, conductor 41 and coupling capacitor 43 to the pulse rate counter which serves as a conversion means for converting the signal into a representation of the parameter being monitored. Expressed otherwise, the pulse rate counter 35 serves as a conver-v sion means for decoding the plurality of pulses sent from each of the radioactivity detectors in the downhole tool. If desired, of course, the respective radioactivity detectors may be connected via respective conductor paths in a coaxial cable with respective channels in the pulse rate counter 35, instead of employing either l) gating where the single conductor is shared by the respective radioactivity detectors, or (2) use of positive and negative pulses as the respective de- I tector outputs so each detector has its own discrete signal. In the case where the radioactivity detector 23 is of the dual type, the recorder will have a pen for each of the two radioactivity detector outputs. In any event,

the quantitative determination of the amount of,

radioactive material flowing past the respective detectors will serve to indicate whether or not a portion of r the radioactive material is being flowed into a strata intermediate the two radioactivity detectors. The relative indication of the quantity of fluid flow past the two respective detectors at their respective depths in the borehole is displayed by a representation on the low pass filter which will pass the casing collar locator signal but will reject the higher frequency signals including those from the radioactivity detector 23.

Many of the respective elements in the surface equipment are, per se, conventional. For example, the

direct current power supply B 33 is of a conventional and well known type used as the power supply for radioactivity detectors and need not be shown or described in detail herein. The recorder 37 is a conventional strip chart, null-balance type recorder.

' The direct current power supply A" 25 is poled oppositely from the direct current power supply B" 33, as implied hereinbefore. Expressed otherwise, the ungrounded terminal of the direct current power. supply A 25 is negative, while the ungrounded terminal of the direct current power supply B 33 is positive. Moreover, the direct current power supply A 25 is a current regulated supply, as indicated. Current regulated direct current power supplies are conventional and need not be described in detail. The DC. power supply A is current regulated in this particular application so that the resistance of the wireline; which may vary depending on suchthings as itslength, and temperature of the wellbore in which it is employed; will not affect the interval of time it takes for the motor to turn through the predetermined degrees of angular rotation and eject the predetermined quantity of fluid. Expressed otherwise, by using a current regulated supply, there will always be a preselected current output from the power supply A 25, regardless'of the length of the wireline, and this current is properly preselected to cause the motor 47, FIG. 2, in the ejector section 19, FIG. to preform properly. Furthermore, with a current regulated supply, when the shunt across the motor is applied, as described hereinafter, the current regulated power supply is not adversely effected; whereas, if the supply were not current regulated, then the current would exceed desired limits, particularly if the resistance in the wireline happened to be low.

Referring to FIG. 2, conductor 51 corresponds to the common or grounded portion of the wireline 15, while the conductor 41 corresponds to the ungrounded conductor 41 of the wireline 15. A circuit may be traced from the terminal 53 connected with conductor 41 serially through a unidirectional current flow device, such as diode 49, via conductor 55, the armature of the motor 47, and conductor 57 to the conductor 51. A capacitor 59 is connected from conductor 55 in series with the normally closed contacts of a switch means, suchas a microswitch 61, to the conductor 57. Thus, with the motor 47 running, the capacitor 59 and switch 61 are serially connected together and in parallel with the motor 47, so the capacitor 59 is charged when the motor 47 is running. In the circuit, an electronic switch means is connected functionally in parallel with the motor and normally nonconductive. The bias circuit of the electronic switch means is connectable by the switch 61, when it is in its second position, with the capacitor 59 so that the electronic switch is rendered conductive upon discharge of the capacitor to effect dynamic braking of the motor 47. Specifically, an SCR (silicon control rectifier) 63 has its cathode 65 connected via conductor 67 with conductor 55; and has its anode 69 connected to conductor 57. The SCR has its gate 71 connected in series with resistor 73 to the conductor 55, the SCR being nonconductive when the motor 47 is running and the SCR is isolated from capacitor 59. The juncture of the resistor 73 and the gate 71 is connected with normally open contacts 75 of the switch 61. Thus, when the switch 61 is moved to its terminal means 81 and conductor 83. The terminal means 81 is readily accessible for connection with a surface power supply of polarity opposite from the polarity of DC. power supply A" 25 for reversing the direction of rotation of the motor 47 and refilling thev reservoir in the ejector section 19 with the fluid to be ejected.

Referring to FIGS. 3 and 4, the ejector section 19 comprises a motor 47 a metered dispensing means 85 for ejecting the fluid in a quantity that is responsive to the degrees of angular rotation of the motor, and a measuring and stopping means 87 connected with the motor for measuring when predetermined degrees of angular rotation have been effected and stopping the rotation of the motor. Specifically, the motor 47 is mounted at a fixed location longitudinally of the housing 89, as by cut away cylindrical framework 91 and mounting screw 93. The motor 47 may be any of the commercially available DC. motors such as the permanent magnet type motors supplied by the Globe Division of Thomas Ramo Woolridge, Inc., Dayton,

and screw housing is referred to in the art as a bearing type lead screw and is commercially available; for example, from Beaver Precision Products, Inc., a subsidiary of Warner Electric Brake and Clutch Company, Troy, Michigan, specification Beaver R-0308. These bearing type lead screws are characterized by high efficiency and relatively low power loss through friction. Consequently, the screw housing 107 is moved reciprocally in response to rotational movement of the shaft 95 of the motor with relatively high degree of efficiency. The cavity 109 receives the screw 97 to accommodate the reciprocal movement of the screw housing, or beaver nut, and beaver nut holder 111 that is attached thereto. The nut holder 111 is attached to rod I rotation of the shaft 95 of the motor 47. The screw,

beaver nut 105, beaver nut holder 111, and rod 113 serve as means for converting rotation of the motor 47 into lineal movement of the piston 119.

An ejection passageway 123 is provided from the lower end of the cylinder 121 to an ejection aperture 125 on the lower sub 127. Disposed in the ejection passageway 123 adjacent the ejection aperture 125 is a check valve 129. The check valve 129 is of conventional construction wherein a ball 131 is maintained against a suitable seat by a spring 133. The spring 133 is weak enough to allow ejection of the fluid under the positive pressure generated by downward movement of the piston 119 but is strong enough to oppose ejection of the fluid in response to small pressure fluctuations; such as, those accompanying the Bernoulli effects created by relative movement between the ejector section 19 and fluid in the borehole 13. Thus, the ejection passageway is maintained full of the fluid to be ejected so that an exact and predetermined quantity of fluid may be ejected each time the predetermined degrees of angular rotation of the motor is effected, as for an ejection cycle.

. The respective sections of the borehole tool are suitably interconnected as by threaded connections with appropriate electrical connector plugs and sockets. For example, as indicated, the housing 89 of the upper ejector section, 19 is connected with the cable head 17. Similarly, the casing collar locator section 21 is connected by a threaded connection with the bottom sub on the ejector section 19. Respective female and male threaded connections 137 and 139 on the top and bottom subs are typical interconnection means. The respective subs are joined to the respective cylindrical housings by appropriate threaded connections and appropriately sealed against pressure from the wellbore. Specifically, the upper and lower threaded connections 141 and 143 and conventional O-ring-installations 147 and 149 sealingly connect the housing 89 to the top sub 14S and to the upper sub 117. Also, the rod 113 is sealingly mounted within the bore 115 to prevent the unwanted influx of borehole fluids along the rod 113. The bottom portion 150 of the ejector section 19 is sealed similarly as was the upper housing 89 to prevent invasion of borehole fluids thereinto.

On the other hand, an aperture 151 is provided in the upper end of the cylinder 121 to allow theinflux of borehole fluids into the cylinder 121 above the piston 119. This equalizes the differential pressure on each side of the piston 119 and further provides increased accuracy of ejection, since movement of the piston is effected independently of the external pressure of the fluids in the borehole.

As indicated by the descriptive matter hereinbefore, electrical continuity exists through the ejector section 19 and into the casing collar locator section 21 and the radioactivity detector section 23. The upper connector 155 is in effect a terminal for the conductor corresponding to the wireline conductor 41. This conductor is connected, via conventional means not shown, downwardly through the ejector section 19 to lower connector 157, which, of course, connects with the next section such as the casing collar locator section 21. The running of the conductors through a tool is conventional and is omitted herein for clarity of illustration. When the ejector section 19 is above ground and it is desired to withdraw the piston 119 for refilling the cylinder 121 with fluid, the motor 47 is run in reverse direction by inserting an insulated probe through the bore of the upper connector 155 with the probe contacting the end of the screw 159 serving as the terminal 81, FIG. 2. The conductor 83 then bypasses the diode 49 for running the motor 47 in reverse direction. The upper connector is also connected via diode 49, FIG. 2, and not shown in FIG. 3, for operating the motor 47. The capacitor 59 and the SCR 63 are interposed physically between the motor and the screw 159 and are electrically connected as illustrated in FIG. 2.

The measuring and stopping means 87 comprises a wafer 161, FIGS. 3 and 5, whichis fixed by means of a set screw 163 to the screw 97, which is connected with the shaft 95 of the motor 47. The wafer 161 has a plurality of threaded apertures 165, FIG. 5, for receiving a screw 167- having a protruding head to serve as a part of the cam actuator 79, FIG. 2. The head of the screw 167 J depresses the arm 169 of microswitch 171 serving as the switch 61, FIG. 2. Thus, it can be seen that as the motor 47 starts to rotate, the head of the'screw 67 is moved from the arm 169 allowing the switch 61 to be moved to the normally closed first position connecting the capacitor 59 directly in parallel with the motor 47 as illustrated in FIG. 2. Only one screw 167 may be employed to allow a complete revolution of the screw 97. Any desired number of screws may be employed to stop the motor a plurality of times for each revolution of the screw 97. For example, as many as four screws may be employed in the threaded apertures in the embodiment of FIG. 5; to allow a proportionately lesser number of degrees of rotation. To illustrate, if two diametrically opposed screws 167 are employed, the motor will be stopped each time the screw 97 is rotated Thus, by providing more cam surfaces such as the head of screw 167, smaller quantities of the radioactive material serving as the fluid may be ejected during each ejection cycle. More fluid may be ejected by employing a counter to allow a plurality of revolutions of the screw 97, if desired.

Operation of the apparatus of the invention will now be described. Assume that the cylinder 121 is fully charged with the radioactive material and the piston 119 is in its fully retracted, or upper, position. The downhole tool 11 has traversed borehole 13 to the desired measurement depth; for example, as accurately determined by the indications of the casing collar locator section 21. The contacts of the switch 31 are in the position shown in FIG. 1 so that power is being supplied is only slightly longer than it will take for the motor 47 to make one revolution, when only one cam actuator surface in the form of screw 167 is employed on the wafer 161. As soon as the push button switch 30 is depressed, switch 31 is actuated so as to close the circuit from the direct current power supply A 25 to the wireline conductor 41. The switch 31 remains in this position for the timed interval and then returns to the position shown. During the timed interval, a negative direct current power pulse is applied on the conductor 41 of the wireline 15. This negative power pulse is conducted through the diode 49 and the armature of the motor 47 so that the motor rotates, or runs. The capacitor 59, FIG. 2, charges during the time interval when the motor 47 is running so that it will be ready to discharge through the resistor 73 when the switch 61 is moved to the position opposite that shown. The motor 47 will continue to rotate until the cam actuator 79, or the head of screw 167, moves the contacts of the microswitch 171, or switch 61, FIG. 2, to the position opposite that shown. When the switch 61 is moved to effect closure with contact 75, the capacitor 59 will discharge through the resistor 73 placing a bias on the gate 71 of the SCR 63 such that it is triggered to the conducting state. The SCR 63 is of a type such that, once triggered, it continues to be conductive until its anode current is removed, as by the expiration of the timed interval and the return of switch 31 to the position indicated in FIG. 1. Once the current is removed, however, the SCR becomes nonconductive and the motor 47 will start to rotate when power is again supplied by way of conductors 41 and 51. When the SCR 63 is in the conducting state, it acts as a shunt for the armature of the motor 47, thus effecting dynamic braking of the motor 47 to a stop. This arrangement thus causes the motor 47 to run through a predetermined degrees of angular rotation and substantially for a predetermined interval of time following the depressing of the push button switch 30. Since the motor 47 runs for the predetermined degrees of angular rotation, the piston 119 is moved a predetermined distance within the cylinder 121 and thus ejects a predetermined quantity of radioactive material through the ejection passageway 123 and ejection aperture 125 into the borehole.

As indicated, the timed interval of the timed relay expires shortly after the rotation of the motor 47 is stopped, and the switch 31 again connects the radioactivity detector 23 with the pulse rate counter 35 via capacitor 43, FIG. 1. Thus, the presence of the radioactive material may be detected as it is flowed past the radioactivity detector 23. A suitable first signal is sent to the pulse rate counter which generates a representation, or second signal, that is suitable for recording on the recorder 37 to effect a visual record of the movement of the radioactive material past the radioactivity detector 23.

Each time the push button switch 30 is depressed, the counter 27, which is connected in series with the direct current power supply A" operates to count the ejection, and there is an attendant ejection cycle as described hereinbefore. A typical ejection volume may be about 1 cubic centimeter when the motor 47 rotates one revolution. A typical ejector section 19 may have a piston cylinder volume, or capacity, of about cubic centimeters. Thus, there could be 30 ejections of 1 cubic centimeter each on a single trip of the downhole tool 11 into the borehole. The number of ejections would always be visually indicated to the operator so he knows the status of the tool.

After the desired logging of a sector of the borehole has been effected, the downhole tool 11 may be returned to the surface and refilled with fluid as described hereinbefore for logging-a different sector of the borehole or another borehole.

The usual materials of construction that are employed in this art may be employed herein and no exotic new materials of construction are necessary.

It can be seen from the foregoing descriptive matter and drawings that the invention accomplishes the objects and provides the desirable features enumerated hereinbefore and not provided by the prior art devices. Specifically, the invention provides a motorized ejector. section for a downhole tool using means responsive to rotation of the motor through a predetermined output shaft angle to eject an accurate predetermined quantity of a fluid into the borehole; and, in specific embodiments, to further improve the accuracy by providing suitable check valves at the effluent aperture and by providing dynamic braking on the motor to resist the tendency to coast after power is denied it. In addition, the invention provides a timed power pulse only slightly longer than the on time of the motor sothat accurate monitoring of the parameter that is responsive to the ejected fluid is carried out almost immediately following the ejectionof the fluid and without requiring a plu-' rality of conductors in the cable and hence, a more expensive cable.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure is made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

What is claimed is:

1. In apparatus for ejecting a metered quantity of a fluid in a borehole penetrating subterranean formations; the apparatus including:

a. a downhole tool having a fluid storage means and a motor for effecting ejection of said fluid; power supply means for supplying power to said motor; and

0. surface equipment having control means for in- 1 itiating rotation of said motor; the improvement comprising:

a quantity that is a function of the degrees of an gular rotation of said motor; and measuring and stopping means connected with said motor for measuring when a predetermined quantity of fluid has been ejected as indicated by said degrees of angular rotation of said motor and for stopping the rotation of said motor regardless of the position of said control means in said surface equipment.

2. The apparatus of claim 1 wherein said apparatus is adapted to effect repetitive cycles of ejection of a metered quantity of said fluid by actuation of said control means after said motor has been stopped by said meametered dispensing means for ejecting said fluid in Q. rotation of said motor to eject from said cylinder a quantity of said fluid that varies linearly with the degrees of angular rotation of said motor; and means is provided for converting rotation of said motor into lineal movement of said piston.

5. The apparatus of claim 4 wherein said motor is a direct current motor and said measuring and stopping means comprises a shunting and braking means for effecting dynamic braking of said motor and an actuation means that is responsively connected with said motor for actuating said shunting and braking means in response to rotation of said motor through said degrees of angular rotation, thereby effecting dynamic braking of said motor for ejecting an accurate predetermined quantity of said fluid each time said motor is energized for an ejection cycle.

6. The apparatus of claim 5 wherein said shunting and braking means comprises a first switch means and a capacitor, said first switch means and said capacitor being serially connected and in parallel with said motor when said first switch means is in a first position; and a second electronic switch means that is connected in parallel with said motor and normally nonconductive, the bias circuit of said second electronic switch means being connectable via said first switch means when the latter is in a second position in series with said capacitor so that said second electronic switch means is rendered conductive upon discharge of said capacitor to effect dynamic braking of said motor; and wherein said actuation means comprises at least one cam means responsively connected with the shaft of said motor and disposed so as to move said first switch means from said first position to said second position after said degrees of angular rotation of said motor have been effected and to allow return of said first switch means to said first position when rotation of said motor is thereafter initiated.

7. The apparatus of claim 6 wherein a plurality of saidcam means are disposed at predetermined degrees about a shaft that is driven by said motor so as to stop said motor a plurality of times for eachrevolution of said shaft.

8. Apparatus for ejecting a metered quantity of a fluid into a borehole penetrating subterranean formations and monitoring a parameter that varies in response to quantitative presence of said fluid comprising:

a. cable means;

b. downhole tool connected with said cable means and including;

i. fluid storage means and a motor for effecting ejection of said fluid;

ii. metered dispensing means connected with said motor for ejecting said fluid in a quantity that is responsive to the degrees of angular rotation of said motor;

iii. measuring and stopping means connected with said motor for measuring when a predetermined quantity of fluid has been ejected as indicated by said degrees of angular rotation of said motor and for stopping the rotation of said motor regardless of the position of a control means at the surface;

iv. sensor means for monitoring said parameter, said sensor means being connected with said cable means for sending to surface equipment a first signal that is representative of said parameter;

c, first power supply means for supplying power to said motor;

d. second power supply means for supplying power to said surface equipment and said sensor means; and

e. surface equipment for decoding said signal and displaying a representation of said parameter; said surface equipment being connected with said cable means and including:

i. a conversion means for converting said signal into said representation of said parameter;

ii. recorder means connected with said conversion means for displaying said representation of said parameter; and

iii. control means for connecting said motor with said first power supply means for initiating rotation of said motor. I

9. The apparatus of claim 8 wherein there is provided a timed relay means that includes a switch means and that is operable into a first condition and a second condition; said timed relay means maintaining in said first condition said second power supply means connected with said surface equipment and said sensor means and effecting in said second condition switching .so as to connect said first power supply means withsaid motor for a predetermined time interval that is only slightly longer than the time interval necessary for said motor to turn through said degrees of angular rotation to eject said predetermined quantity of said fluid and for said measuring and stopping means to stop rotation of said motor.

10. The apparatus of claim 9 wherein said timed relay means is connected to a manual switch means for being operated into said second condition upon closing of said manual switch means.

11. The apparatus of claim 8 wherein said apparatus is adapted to effect repetitive cycles of ejection of said predetermined quantity of said fluid by actuation of said control means after said motor has'been stopped by said measuring and stopping means.

12. The apparatus of claim 11 wherein a counting means is connected with said first power supply means so as to advise an operator of the number of ejection cycles that have been carried out and the quantity of fluid that has been ejected and, consequently, how much of the original quantity of fluid remains to be ejected.

13. The apparatus of claim 8 wherein said metered dispensing means comprises a piston that moves linearly within a conforming cylinder in response to rotation of said motor to eject from said cylinder a quantity of said fluid that varies linearly with the degrees of angular rotation of said motor; and means is provided for converting rotation of said motor into lineal movement of said piston.

14. The apparatus of claim 13 wherein said motor is a direct current motor and said measuring and stopping means comprises a shunting and braking means for effecting dynamic braking of said motor and an actuation means that is responsively connected with said motor for actuating said shunting and braking means in response to rotation of said motor through said degrees of angular rotation, thereby effecting dynamic braking of said motor for ejecting an accurate predetermined quantity of said fluid each time said motor is energized for an ejection cycle.

15. The apparatus of claim 14 wherein said shunting and braking means comprises a first switch means and a capacitor that are serially connected together and in parallel with said motor when said first switch means is in a first position; and a second electronic switch means that is connected in parallel with said motor and normally nonconductive; the bias circuit of said second electronic switch means being connectable via said first switch means when the latter is in a second position in series with said capacitor so that said second electronic switch means is rendered conductive upon discharge of said capacitor to effect dynamic braking of said motor;

and wherein said actuation means comprises at least one cam means responsively connected with the shaft of said motor and disposed so as to move said first switch means from said first position to said second position after said degrees of angular rotation of said motor have been effected and to allow return of said first switch means to said first position when rotation of said motor is thereafter initiated.

16. The apparatus of claim 15 wherein a plurality of said cam means are disposed at predetermined degrees about a shaft that is driven by said motor so as to stop said motor a plurality of times for each revolution of said shaft.

17. The apparatus of claim 8 wherein said downhole tool has in its ejection passageway a check valve means that allows ejection of said fluid at a predetermined pressure, prevents unwanted back fiow of fluid in said downhole tool, and provides sufficient closing force to prevent weeping of said fluid from said downhole tool because of relative movement between said downhole tool and any fluid in said borehole and attendant differential pressure such as induced by Bernoulli effects.

18. The apparatus of claim 8 wherein said motor is a same direction in downhole operation for ejecting said I fluid and is reversed at the surface for refilling with said fluid.

19. The apparatus of claim 18 wherein said first power supply means is a current regulated power supply means for effecting a more nearly uniform rate of rotation of said motor regardless of the length of said cable means or the depth at which said motor is disposed in said borehole.

. 20. The apparatus of claim 8 wherein said first power supply means is a current regulated power supply means.

21. The apparatus of claim 8 wherein said fluid comprises a radioactive material said parameter comprises a product of the radioactivity of said radioactive material, said sensor means comprises a sensor that measures quantitatively said product of said radioactivity-and produces a series of pulses as said signal, said conversion means comprises a pulse rate counter that produces a voltage output that is a representation of the number of pulses per unit time, and said recorder means is advanced in proportion to time to display said representation as a function of time.

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Classifications
U.S. Classification166/53, 166/104, 166/64, 166/66, 166/169
International ClassificationE21B47/10, G01V5/00, E21B27/00, E21B27/02, G01V5/08
Cooperative ClassificationE21B47/1015, G01V5/08, E21B27/02
European ClassificationE21B47/10G, G01V5/08, E21B27/02